New construction, garage, swimming pool...: what effect on local taxes?
Verified 28 January 2026 - Public Service / Directorate of Legal and Administrative Information (Prime Minister)
Swimming pool, garage, veranda, etc., any new construction increases the value of your home and therefore the amount of your local taxes. You have to do a land declaration after its completion.
A new construction increases the rental value which is used to calculate property tax and the housing tax on second homes.
The improvement may result from a new isolated construction or a modification of an existing building by its extension, elevation or change of destination. The extension or modification may concern the main building or the annexes and outbuildings.
All constructions or expansions are concerned, whether they have or not is the subject of a city planning authorization (prior declaration of works, building permit).
This is the case in particular for the following constructions:
- Terrace
- Swimming pool
- Veranda
- Garden shelter
- Garage
- Extra room.
The new construction must be declared if it is impossible to move it without demolishing it (it is said to be fixed to the ground to perpetual abode).
Example :
A swimming pool, whether buried, semi-buried or above ground, is affected if it cannot be moved without demolishing it.
You must declare the new construction no later than 90 days after completion of the work.
You have to make your land declaration on your personal space as a remote registrant in the “Real estate” section:
Taxes: access your Public Finance space
The “Real estate” page of your personal area allows you to view all the real estate that belongs to you. Each property is represented by a pictogram. You can consult the information known by the tax administration for each property. If you have done any work, you must refresh the description of the property concerned.
If you had asked for a city planning authorization before starting your new construction, you will find the mention “Expected land declaration”. You must then click on the “Declare” button located under the property concerned by your work.
A form must be completed:
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New construction of an isolated outbuilding (garage, greenhouse, swimming pool)
Change in the consistency or use of an existing building
Send your completed form to the property tax center of the place of construction no later than 90 days after completion of the work.
Example :
For a pool, indicate the imposition elements, such as the completion date, the characteristics of the pool, the surface of the pool.
Filing the return within 90 days may allow you to obtain a exemption from property tax for developments or new construction for 2 years.
You must update the description of your property on your personal space as a remote registrant in the "Real estate" section:
Taxes: access your Public Finance space
A form must be completed:
Répondez aux questions successives et les réponses s’afficheront automatiquement
New construction of an isolated outbuilding (garage, greenhouse, swimming pool)
Change in the consistency or use of an existing building
Send your completed form to property tax center of the place of construction.
Please note
If the tax authorities detect an undeclared construction (swimming pool for example), they send you an email to invite you to regularize your situation. In that case, you have 30 days from the receipt of the email to make your declaration.
Who can help me?
Find who can answer your questions in your region
- Property Tax Center and Cadastre
By phone:
0809,401,401
Monday to Friday from 8:30 am to 7 pm, excluding public holidays.
Free service + price call
Determination of property tax on the basis of the cadastral rental value (Article 1388)
Declaration of new constructions, changes in consistency or use
Determination of housing tax on the basis of cadastral rental value (Article 1409)
Service Public
Service Public
Ministry of Finance
Ministry of Finance